Probably not worth making a カラーキー/カラー・キー entry as the gloss would be a problem. I'll index the カラー in that sentence to sense 4.

https://ja.wikipedia.org/wiki/キー

That's a separate sense but I'm not sure it's needed, especially if it only appears in compounds. There are plenty of other technical meanings of キー/"key" that I didn't bother to include.

@@ -27 +26,0 @@
-<gloss>code</gloss>

Tanaka:
カラー・キー・プログラム・システムでは全ての色が「クールパレット」と「ウォームパレット」の２つに分けられる。  With the colour key program system, all colours are divided into two palettes, the "cool palette" and the "warm palette".

The sentence uses カラー・キー. Here キー means code. I'm suggesting that be added to sense 4, but it could be a new sense.
I've reindexed some sentences.

@@ -26,0 +27 @@
+<gloss>code</gloss>

gg5, daij, meikyo

Splitting into senses.

@@ -11 +11,21 @@
-<gloss>key (lock, keyboard, piano, clue, island, cay, etc.)</gloss>
+<gloss>key (for a lock)</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
+<gloss>key (of a piano, organ, computer keyboard, etc.)</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
+<xref type="see" seq="1956690">調・1</xref>
+<field>&music;</field>
+<gloss>key</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
+<gloss>key (to solving something)</gloss>
+<gloss>clue</gloss>
+</sense>
+<sense>
+<pos>&adj-f;</pos>
+<gloss>key (person, point, etc.)</gloss>
+<gloss>most important</gloss>